Depends what you consider "lots". Pound for pound, it's way behing the others. One 15g leaf of iceberg has 75 IU of Vitamin A, or about 2% of your RDI. A single leaf of bibb lettuce has five times that amount (497 IU) and half a leaf of romaine (14g) more than 10 times (813). But the real winner is spinach. 14g have a staggering 1642 IU or a full third of your RDI. The numbers are comparable for other vitamins like C and K, minerals like calcium and iron, and protein.

That's why, if I'm going to invest some energy into munching on greens, I prefer to make it lettuce wherever possible. If I want crunch, I'll add red cabbage or raw onions.